Am I overreacting?

I just want to make it clear that my SO did not say that I was, nor did he say that I was in the wrong for being upset.

My SO and I have been engaged for around 3 months now, and his ex fiance has been in boot camp. He is currently deployed and today he texted me telling me he has to removed from Facebook that we are engaged as his ex fiance has some things that belong to him and being she's coming home she'll get pissed to see he's engaged, and will destroy these belongings. The belongings being his grandfather's shadowbox.

I'm not a big social media person, so social media is not at all that big of a deal, but I was instantly upset over this. I understand that he doesn't want his belongings destroyed, but I honestly think it's wrong of him to remove that he's engaged to, in my opinion, spare her feelings. He told me the only reason he's doing it is so that he can get his belongings back. So like an I wrong for being upset? Its obviously not something I'm going to destroy my relationship over, but I'm not letting him get away with thinking this is okay with me.